Marcus,
I so appreciate you getting back to me as it helps me learn. I guessed your Pad Y around 620 but it's really 635 - that's good for me to know. 15mm is pretty close and I try to prescribe a bit that will have some range around my speculation.

I think you should ride a 155 crank. You're gonna have to leave the big brands for that and get a Cobb (SpeedandComfort.com) or a Rotor. Because your morphology is built more from a long torso you can ride longish and lowish but only if the cranks are short enough.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hello Ian,

My first post in years. I am interested in the PRSix or PRSix2. Let me know if the following measurements sound correct. I currently use a 2007 P3C size 51 and crank length 170 mm.

Height: 172 cm
Inseam: 76 cm
Saddle Height: 686 mm
Pad Y: 575 mm
Pad X: 477 mm

Thank you for your assistance!

V/r,
Richard

I am new to the tri purchase space and fear I've gotten myself into a bind. I could really use some perspective on what I have (fitting and bike) to inform my next moves.
Current Situation: I have a 54 PRfour disc. For a variety of reasons, I no longer want to work with the fitter that gave me the numbers below if it can be avoided. I'm partnered with a new LBS that's between fitters but doing their best to adjust my PRfour to the fit numbers we have from the original fitter. However, that LBS is really struggling and the numbers seem wildly off. For example, the LBS is interpreting that the reach is off by 10 CM. This seems crazy given that the original fitter suggested that a M Shiv or a 54 Felt IA were 'dead on' for reach. I know there are many other factors that go into setting the cockpit but 10 CM seems way off.

Numbers I was provided

• Saddle top to BB = 650
• Saddle top to C BB = +12
• Saddle Tip to Aerobar Tip = 650
• Saddle Top to Back of Pad = 290
• Elbow Pad Width = 270
• Crankset = 172.5

My questions:

1. Did my original fitter give me enough to work with (what I'm seeing on the form looks far less detailed than what others are providing in this thread)?
2. If they did, do the numbers make sense (the new LBS are struggling with them)?
3. Are my fit numbers sufficient to determine, if a 54 PR four would work for me?
4. If the numbers make sense but the bike doesn't fit, what other sizes/bikes in the PR family would be recommended?

Richard,
Thank you for honoring this thread with your big return to the ST Forum. Keep 'em coming!!!

Your numbers seem logical - you ride a bit lower than I'd expect but that's fine.

For the QRPRsix or six2 (same size/fitting prescription)... you'll ride a size 48* with a 110 stem, the stem clamp in the low position (there's a clam shell inside the stem clamp that holds the bar. The low position means you'll put both sides of the clam shell on top of the base bar to set it up lower). Then add 15mm of aero bar pedestal. Arm pad bracket needs to be set up rear-word and then the arm rest itself will be in rear hole. *Don't freak at the 48cm frame size. QR sizes their bikes is a super logical way (48 means the frame stack is 480mm - so smart but virtually unused in the bike biz). It makes it sound weird that a guy your height would ride a 48 but you ride low so it's the right bike for you.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

tfizz,
I want to help and I think I can. Here's what I need:
Your height, inseam, and I want your seat height too - it might be 650mm but I'm confused by the the description of the numbers above "saddle top to BB is 650" but then "saddle top to C BB is +12" - Those are questionable.
if you have a fit sheet I want to see that too you.

Get me what you can and let's work through this.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Thank you for the information, Ian! Question, if I want to go with the QR PRsix2, the integrated front hydration isn't available on the size 48 frame. Can I fit on the size 50? Also, in the future, I might not have such an aggressive drop as my current setup.

Richard

Honestly, I don't have context on what went into the saddle top figures (I can try to get an answer from the fitter depending on how critical you think it is).

Numbers I have (in CM):

• Height = 175.3
• Inseam = 83.2

Thanks for your willingness to help. If it helps you, I'm happy to send along the sheet I got from the fitter, though it has mostly what I've covered here.

Your saddle height should be around 73cm.

tfizz,

TL:DR - this bike will fit you. The stem has to be level to the ground in the -17 degree position to make it work and probably little to no spacers under stem or pedestal under aerobars.

The very best way to purchase a tri bike is to go to a fitter than has all of these things: tri fit education, tri fit experience, and a dynamic fit bike (there are only ~5 of these [guru, purely custom, exit, muve, shimano], they are specific to the task). The fitter has to have all three of those things - they can't get by with just 2 out of 3. From that pre-fit process the fitter would have you leave with 2 things: 1) your Pad Y and Pad X. These are the numbers by which we identify bikes that will fit someone. And part of this should be a list of 3-5 bikes that interest you, the size in each brand/model that is right and the front end configuration - where we would put the pads in the right spot for you. 2) All your fit coordinates: seat height, set back, cockpit distance, arm pad elevation, etc. etc. etc. - and for tri there are lots of coordinates to name.

You may have had that experience and we're just not getting the numbers of out it properly. Maybe not, I don't know.

The next best way is to take your old tri bike that has a very good position and measure Pad Y, Pad X off that to identify the new bike but you don't have that. As you said you're new to the tri purchase.

The third best way is to give some details about your morphology to me and let me make an educated guess. This works because we're all human and pretty much the same. If both you and I are rushed to the emergency room in need of an appendicitis they don't cut me above my right hip and cut you above your left clavicle. We're all pretty similar to an extent.

You've got long legs for your height. That's an important detail. I think, based on what you've given me, your Pad Y is somewhere around 625 and your Pad X is ~450. This is assuming you're long leggedness is the big issue to take into consideration, there could be other factors that might impact this (lots of fused vertebra in your lumbar, a round belly that resembles the 7th month of a pregnancy) - but if you're pretty normal than I'm confident with the Y at or near 625 and Pad X roughly 450.

You have a 54cm PRfour... we can get close to this on your bike in three different ways.... here we go.....

1. 54cm PRfour with a 110mm stem set up in the -17 degree position. Slammed - by this I mean no spacers under the stem, no pedestal under the arobars. Then the pads mounted one hole forward of the absolute middle.
2. 54cm PRfour with a 90mm stem in the -17 degree position. Slammed and pads 3 holes forward of all the way back.
3. 54cm PRfour with a 70mm, -17 deg stem, slammed, pads mounted dead center.

If I'm right about the Pad Y then you cannot get that low with the current systems in place*. But you can get close. The lowest you can get is 636/637 (#1 & and #2 above yield 637 and #3 above gets you down to 636mm of Pad Y). That's 16mm higher than I'd assume you ride BUT you might LOVE IT there. It might be perfect. You might even ride higher at 642 or 647 and your bike can meet you there too. Quick side note - the stem cannot be flipped to the +17 position to get even close to these numbers: the lowest the bike goes with the +17 is 680ish. Now, If I'm right about the Pad X then you've got it made because all three of these stems hit on or with/in 1 mm of your Pad X - and there's room to move longer or shorter in your cockpit if I'm off a bit in my guestamation.

*Let's say for a moment that I'm right about the Pad Y being 625...or even, dare I say, you absolutely must ride even lower at 615ish. This bike could still get there. I'm not nuts about what I'm gonna propose but I feel I'd be remiss if I left it out. You could get a stem that's even more angled down than a -17. That's one option. The other is that you remove the clip on aerobars that came with the bike and you installed a set that can be "under mounted" so that you have arm pads that are essentially resting on top of the base bar. This whole paragraph is prolly unnecessary.

There is one thing that is mandatory for all this to work. You must be riding a tri saddle and you must be riding it comfortable in the proper spot (on the front 3/4 of that saddle) for all this to work. If you're ride a road saddle or a tri saddle and sitting way back on it then these numbers won't be close and your position isn't right. The correct saddle for you is critical for success.

Get back to me here with questions.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

 

Richard,
You can ride a 50 and that will give you the two things you mentioned: 1) hydration system and 2) the ability to go up ... a bit.
So the prescription for the 50 is... the 110 stem clamped in the low position and the 110 stem with bracket forward and armrest in middle hole. The Pad Y in this position is the lowest the bike can go and it's 580 (5mm higher than you quoted). The pad is 475 (2mm off). If you think your drop might reduce in the future (many people do that) then the 50 will work!

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Thank you, Ian. This response was helpful is so many more ways that I could have reasonably asked for.

TL:DR - Met with new fitter and gave the 54 PRfour a test ride. We both feel good about it. Threw it on the trainer last night and feel better. Will tweak over the next month or so of trainer riding while the bike paths here thaw out.

Not that you asked for it, but responses to your points (I've abbreviated the quotes of your responses).


The fitter did meet these three requirements. Without assigning blame to either party, I think where things fell down was being super clear on Stack/Reach and the more detailed cockpit configuration details. Basically, I was given a Stack of 540 and Reach of 405 and we did look at two bikes (Shiv and Felt IA) with an explanation of the extent to which they could work. And, because of how things played out, it made the most sense for me to avoid going back to attempt to clarify things further.


Guilty as charged. I also have tight hammies and lower back (and an issue with my left hip socket, though that doesn't really flare up on the bike). I've been really busting my but on flexibility for the problem areas so I can open up more options on fit.


The new fitter didn't see this before finalizing my adjustments. What I've got at the moment is a shorter stem but nothing's slammed at the moment. My elbows seem to have good bend and we've agreed to not worry about trying to hit the height numbers for a bit while I acclimate. Buuuuuut, I've shared this with awesome-new-LBS and we'll use it as a point of reference for that time when we do tweak things.
More importantly, if you're ever in West Michigan, LMK and you'll have a premium craft beer with your name on it, free of charge.



I'm taking the leap that the stock ISM PR 2.0 should get the job done here.

Overall, Ian, I want to thank you. Your response was a huge help. Not only in reassuring me that the PRfour was a workable option for me (b/c, I just love everything about it), but going out of your way to fill in so many other details. I am grateful that I stumbled upon this and for your time and expertise. I'll say it again... you make it to west michigan, give me a heads up so I can do something to return the solid that you've done me.

tfizz,
GREAT NEWS all around!!!

I was born in Pontiac and while my mom lives in Aspen, everybody else (Dad, brother, aunts, nephew, cousins, etc) are scattered around Rochester, Lake Orion, Oxford. My brother and nephew are deeply into lifted, performance monster trucks (HTF am I, and EV driving bicycle nut, related to these people??) go to Silver Lake twice a year to........ brake axles and such. I've been once the dunes are beautiful. I think my next visit home to see the fam will probably be done as a flight to O'hare, ride to Milwaukee, Ferry to Muskegon, and then on a ride that rail trail that takes you to Owosso and then I'll pick and choose to through Flint to Rochester. It intrigues me to ride across the state.

All the best, Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Hi Ian,

Just updating my mesurements on the PRSix and some help on getting it dialed in. Haven’t had my full fit, with the Covid I dont get fitted until May. So making minor adjustments on my bike based on ride feel for now.

Current set up is Pad X 460 and Pad Y 650.
In your initial suggestion, ideally I get to 620-630 on Pad Y. Do I go ahead and put all stem clamps at the top? Will that help get closer to the 620-630 Pad Y?

Morning, Ian. Could you help me pick which size SRFive I should be on? I haven't bought a new road bike in about 12 years and I'm a little overwhelmed with all of the fit information out there now.

I'm 71.5" tall with a 32" inseam. Current saddle height is 29 and 3/8" (top of saddle to center of BB).

I'm currently on a 2008 Orbea Orca (size 54) with a 20mm offset seat post and a 100cm stem. The fit guide on QR's website says I should be on a large SRFive, but the medium looks to have the same geometry as my current bike.

Thanks for your help in advance and for putting up this thread!

Hi Ian

I have a QRPrsix 54cm transitioning over from a cervelo p3 56cm.
this is what I had on the cervelo:

6ft 33.5 leg
saddle height 76cm
saddle to pad 43cm
pad stack 61cm
crank 172.5

I just put the same numbers on the qr. seems pretty comfortable other than I seem to get some strain in my neck and shoulders but not really sure any more than on the cervelo. any suggestions? also if you can recommend bike fitter in Louisville, KY

Scott Kellie

You could post a video here and get a free fit.

jeyps11_c,
Yes, you're headed in the right direction. Pad Y informs...goes hand in hand with Arm Pad Elevation (AKA "drop"). So right now you're riding with a Pad Y of 650. If you remove the "top cap", pull off any spacers that are currently between the top cap and the top of the stem, then loosen the 2 stem clamp bolts and wiggle/twist the stem-basebar-aerobars (basically the whole front end) up and off the steer tube then you can remove just a single 10mm spacer that was under the stem and rebuild* the whole thing with that 10mm spacer now on top of the stem and ta-da, you're now at a Pad Y of 640 - said another way, your drop just increased by 10mm.

BTW... 620-630 is not ideal, it's just an assumption based on what I learned from you here. 625 is not your goal. Your first goal is to be comfortable and powerful. Then if you can maintain comfort and power while reducing your frontal area great. There are two ways you typically reduce frontal area: 1) narrow the arm pads and 1) lower the bars. As you do both of those things - there's a point where you'll start to loose comfort or power of - - gasp, both! Don't get that far.

Ian

*Rebuild in this order: slide stem back down on steer tube. slide all your spacers down the steer tube atop the stem. Then put the top cap on and just tighten it snug. Align the stem with the wheel and then tighten down the 2 bolts on the stem that clamp it back to the steer tube. When you think you've got it.... squeeze the front brake and gently rock the bike forward and back. If you feel a clunk-clunk in the headset then the top cap isn't tight enough or you've left a spacer out of the system. Undo the stem clamp bolts - double check everything and reassemble.

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Brandon,
This post thrills me because it's the first request for a road bike prescription on the thread and man the SRfive is so sweet!!

If I had nothing else to go on but your height I'd say you should get a Large - which is essentially a 57cm bike. And your morphology is so wonderfully normal 5' 11" with a 32" inseam. But you have this 2008 Orca. I tried to dig up the Stack and Reach on that but GeometryGeeks doesn't go that far back. There was one on The Pro's Closet but no Stack and Reach listed.

The top tube on your Orca is 55cm and you rode that with 100mm stem. The top tube on the medium SRfive is 55mm and it comes with a 100mm stem (the FSA ACR - it's the one that hides the cables/hoses). The ONLY thing that could be a fly in the ointment here is this... I bet the bar curve on the SRfive (Vision Trimax) is 76-78mm and that might differ a bit from the bar on the old bike.

I think you should get the medium, it'll get you very close (if not dead-on) the reach of your old bike.

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Scott,
The only two fitters I know of in your area are - Rick Smith at CycleSmiths on Shelbyville Rd and Drew Kallio at DrewKallio.com. I don't know either of those guys and I prefer to refer to fitters I know. So call them and ask a lot of questions and go by your gut feel of their answers.

If your Pad Y is 610 then that's your neck strain. I'd expect you to be 640 and even 630 to me would be lowish - 610 is very low. All this is based on the assumption that we're talking about the same thing here. For 99% of triathlon I'm a firm believer in comfort 1st, power creation 2nd and aero 3rd. Sounds like your a little bit uncomfortable so... I'd come up 10mm and try that.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Ian,
Thanks for providing this advice.
What would you recommend for the following in a PRfive:?

My existing bike is a Cannondale Ironman Slice from around 2007, and my position was not set by a fit.
What about crank length and incorporating some upward tilt to the aerobars?

mm
Inseam: 813
Height: 1738
Saddle Height: 703
Pad Y: 665
Pad X: 354

What crank arm length are you currently using?

Thanks, Jim.
They are 172.5.

kscomp0,
That Pad X gives me pause..... I'm suspicious of a typo or some mismeasurement. If you had just given me your overall height and inseam and I would have guessed a Pad Y of 630 (so your 665 is reasonable) and a Pad X of 450... I could have accepted down to 430... but 354!!! Dubious!!! I just think something went awry in that measurement. Maybe not!

If - if, mind you - your Pad Y is 665 and Pad X is in the range of 440 then the right PRfive would be a size 50 with a 90mm stem in the +17 position with 20mm of spacer under the stem, no aerobar pedestal and pads forward 2 holes from center.

If - if.... your Pad Y is 665 and your Pad X is 354... the only way to get near it... is...
A size 48 with a 70mm stem in the +17 with 30mm of spacer under the stem and 15mm of aerobar pedestal and pads back one hole forward of max and the result is... Pad Y of 659 Pad X 354. It's dead on with the cockpit distance but 6mm lower than your current set up. You could also do a 48 with a 90mm stem, +17, 30mm space, 10mm pedestal and pads back 100% the Y is dead on but the X is 9mm longer than your desired 354.

As to tilt in aerobars - on this bike it's too easy to play with the angle to find something you love. The aerobars are clamped on a round base bar and you can simple loosen 2 bolts, pull 'em into a bit of tilt, tighten and ride. You can find a place that's perfect in one ride with 4-5 stops.

As to crank length - your current 172.5s are just too long by triathlon standards - especially for someone of your height. When you order your QR call them and stay "can I get 160s on this bike" and see what they say. Maybe you have to settle at 165s - which would still be so much better but 160s would be near perfect. Keep in mind... if your crank length shortens, the seat height has to go up. So if you go from 172.5 to 160 the seat height has to go up 12.5mm (to maintain your current saddle height). if that happens your pad drop might need to come up a tiny bit but short cranks allow us to ride lower. All the prescriptions I've give above allow for some room to lift the pads so the bike will still fit you with the shorter cranks.

Ian

Ian

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Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan

Thanks for the great response, Ian! That's a huge help.

In my defense, I'm not the one who read the tape measure...
I retook the measurements, and I did get some different numbers. Albeit, not radically different.

Pad Y of 645
Pad X of 390

I think I see what you are doing as far as picking a size from the QR fit chart.

Does a 52 with 70 mm stem at -17, 0 risers, 3 cm stem spacer, and pads completely back sound right,
or is the 50 with 70 mm stem at +17, 0 risers, and 1 cm stem spacer a better choice?
As this position just evolved over time, I was trying to find something that might work for your guesstimate position as well.
Cheers,
Kevin

kscomp0,
Well, you are right on in terms of reading the prescriber chart, well done. I like the 52 set up better - I like the look of a -17 stem over the +17 and I like the fact that the 52 gives you some flexibility in all directions while the 50 gives you a more limited direction of adjustment.

Ian

---

Ian Murray
http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan